1. Field of the Invention
This invention relates in general to methods for receiving an alphanumeric input string entered using a telephone keypad and for confirming the intended input string using voice prompts, and in particular to an identification method that permits the recognition and confirmation of input strings entered with one keystroke per input string character.
2. Description of the Related Art
Commercially available voice recognition hardware and software systems have become relatively sophisticated and can recognize words and phrases with a reasonably high degree of accuracy. Accordingly, such voice recognition systems have been used to implement voice user interfaces deployed in messaging systems, vehicles, computers, telephony, and other applications. In such systems, similar sounding words may be difficult to distinguish, as may be words spoken in an unusual accent, and the like. Noise (e.g., line noise or noise originating at the sound source) and dropouts typical in telephonic applications can also adversely impact speech recognition accuracy. Accordingly, a telephone keypad type data input method can be a useful adjunct to a voice recognition system for noisy environments, for use in further distinguishing from among similar sounds, or for applications that are to be made available to a broad user base having disparate accents or dialects.
Currently, most touch tone (i.e., dual-tone multi-frequency code or DTMF code) data entry systems utilize a two-keystroke-per-alphanumeric-character text input system, due to the fact that standard telephone keypads do not assign a unique key to each alphanumeric character but instead assign several alphanumeric characters to each individual key. Typically, the first key in each two-key sequence is used to identify a distinct character set, and the second key is used to identify specific character within the set. For example, a telephone query to a stock quote system might require an entry of a sequence such as 6, 1, 7, 3, 3, 3, 8, 1 to input a ticker symbol such as MSFT (i.e., M=<6,1>S=<7,3>, F=<3,3>, T=<8,1>). While such an entry method is accurate, it is slow, cumbersome, potentially confusing, and difficult to learn.
Conversely, if a single key per character input method is employed in an application to enter alphanumeric information, the resultant input sequence may not contain sufficient information to precisely and uniquely determine the specific alphanumeric string intended, and therefore the number of potentially correct responses can be quite large and therefore difficult to present to the user in a readily useful manner.